Abstract: A fishing line trolling release mechanism. One embodiment is for use with a surface planer board line; another embodiment is for use with an underwater depth controlled downrigger-trolling cable and weight system. In either embodiment, the mechanism reduces or eliminates slack line, which results in more consistent hookups while retaining unhindered fish playing ability. The embodiment for board line release is snapped on the planer board line that slides out to the desired distance from the boat. The embodiment for downrigger release is snapped around the downrigger cable, then lowered to the desired depth by the rod and reel, employing a rotating diving and return plate to controls the depth of the combination prior to and after the fish strike.